D = 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991
N = int(input())
X = D*N
# print(X)
x = X//(10**190)
y = X %(10**190)
print(x, end="")
if y>0:
    print(".",end="")
    for i in range(189, 1, -1):
        if y<10**i:
            print(0, end="")
    print(y)